Electric telephony



(No Model.)

A. G. SAFFORD.

ELECTRIC TELEPHONY. No. 366,190. Patented July 5,1887.

\Q- Wikmooao UNITED STATES FFICEQ PATENT ALFRED G. SAFFORD, OF IVASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR OF ONE-HALF TO L. L. BULLOCK, OF OAKLAND, CALIFORNIA.

ELECTRIC TELEPHONY.

SPECIFICATION forming part of Letters Patent No, 366,190, dated July 5, 1887.

Application filed January15,1887. Serial No. 221,462. (No model.)

To aZZ whom, it may concern.-

Be it known that I, ALFRED G. SAFFORD, a citizen of the United States,residing at \Vashington, in the District of Columbia, have invented certain new and useful Improvements in Electric Telephony, of which the following is a specification.

My invention relates to reed electric telephones; and the objects of my improvements are to provide a more thorough demagnetization of the induction'head of the combined permanent magnet or cores of the electromagnet, and also to provide a resonant sensitive series of tuncdreeds for the reception of the [5 electro-motive force of the magnets as varied by the energy transmitted from the dist-ant station.

In the drawings, Figure 1 is a longitudinal cross-section of the magnet. Fig. 2 is a transzo verse cross-section of the soft-iron inductionhead. Fig. 3 isafroiitview of the tuned reeds. Fig. 4 represents the frame to which the reeds are attached and by the peculiar form of which the several reeds are tuned. 2 5 I am aware that magnets having soft-iron induction-heads and a series of cores surrounded by coils of insulated wire have long been used both for telephonic and other purposes. The same have not, however, been 0 used in combination with attuned reeds, and I make no claim except for such combination.

I am also aware that reeds, as distinguished from a solid plate, have been used in the construction of speaking apparatus; but my in- 3 5 vention provides for the attuning of said reeds through an entire octave and covering at least one reed for each semitone of the diatonic musical scale.

I am also aware that tuned reeds have been suggested for this purpose; but the limitation and qualification of the suggestion was, that all the reeds in the same instrument should be attuned to the same pitch-that is to say, that each reed should have in the same instrument the same natural rate of vibration. My invention proceeds upon the contrary theory, and depends for its usefulness upon the fact that the free vibratory reeds are to be attuned to different rates of vibration. of said reeds may be increased indefinitely and through one or more octaves.

The number In Fig. 1, N S is a permanent magnet. A represents the wire from one or more distant stations under electric control. B represents the spool containing the insulated circunr volved wire. The faces C and D of the spool 13 are of soft iron or other metal capable of inductive action.

In Fig. 2 the magnet is not presented, nor the face D of the spool B; but the soft-iron cores a, b, 0, d, e, and f are shown, together with the soft-iron screw-plug E, which holds the spool firmly and in its entirety against the magnet N S. The wire A is wound succes sively around the cores and screw-plug until sufficient resistance is attained. 'But one convolution is shown in the drawings. The two faces of the spool 13 and the connecting-cores are magnetized by induction from the magnet NS. The electromotive force of the soft-iron 7o induction-head remains constant until achange takes place in the electrical condition of the wire A, when it is increased or diminished, according as the electrical impulses in the wire Acoincide wither are opposite to the 7 character of the induced magnetism. If that induced magnetism be positive and the electrical impulse be positive, then the electromotive force is increased. If it be negative, the electro-motive force is decreased, and the increment and decrement of the force is measured relatively by the strength and pulsation of the transmitted electrical energy. If that energy be a continuous varied one, the same variations are developed in the electro-motive force.

Fig. 3 shows the attuned reeds which are set up on the frame F immediately in front of the magnet and circumvolved insulated wire, (shownin Figs. 1 and 2;) and said reeds being 0 made of material capable of inductive action, the variations in the electro-motive force of the softiron induction-head are communicated to said reeds. Said reeds are free and vibratory, so fashioned as to present nearly a continuous 9 5 surface to the action of the charges in the electro-motive force of the spool 13. Said reeds are so constructed and attached to the frame F that they have different natural rates of vibration, or more than one may be tuned to the same rate of vibration; but altogether they present atleast one reed for each semitone of an entire octave of the diatonic musical scale. The frame F has flanges G G G which facilitate the tuning of the reeds by shortening the vibrating end. As thus constructed, said reeds respond very readily to all sounds or to timbre, which marks the difference between those sounds having the same pitch and the same force.

In the construction of my improved instrument, I prefer to arrange the reeds upon acircular frame with the free ends pointing toward the center and with three scales of twelve semitones each, each scale commencing with the thesame fundamental tone. This method brings all the reeds within the field of the electromotive force and brings three reeds having the same natural rate of vibration and representing each seniitone at equal distances apart. WVhen the electro-motive force is varied in the soft ironof the spool B, all the reeds attached to the frame F are thrown into corresponding vibration; but with every vibration some of the reeds respond more readily than others,by reason of the principle of co-vibration, and become sonorous if the impulses correspond to the normal pitch or natural rate of vibration of said reeds or any multiple thereof. Some of the reeds vibrate to any and all sounds in this manner and reproduce the sound transmitted. They are re-enforced by the vibration of all the other reeds, and the sound thus produced may be carried to the ear by any kind of deflective apparatus which shall convey the s0und-waves to a common point; and by this means sounds which have been used at a distant station to produce variations in an elec-' trical current, whether the same be musical or complicated, such as articulate speech, are by means of the wire A, the spool 13, the magnet N S, and the attuned reeds reproduced and rendered audible at the receiving-station,with all their characteristics of relative pitch, intensity, and quality.

I expressly acknowledge the fact that prior electrical devices; but

vVhat I claim as my invention, and desire to secure by Letters Patent, is

1. An inductive spool, B, having several cores of soft-iron or other inductive material connecting its faces, around which the insu; lated wire is successively wound, in combina tion with a series of attuned reeds, substantiall y as set forth.

2. In a telephone, a series of free vibratory reeds attuned to different rates of vibration and brought within the field of the actuating electro-motive force, for the purpose of making the variations of such force appreciable as audible sounds.

3. In a telephone where the electro-motive force is received upon free vibratory attuned reeds, the combination of said reeds with the frame F, having the flanges G G G for the purpose of attuning the said reeds to different rates of vibration, substantially as set forth.

4. The combination of a magnet in telephones with a series of reeds attuned to different rates of vibration and capable of inductive action, for the purpose of transmitting and reproducing vocal or other sounds, substantially as set forth.

ALFRED G. SAFFORD. \Vitnesses:

JAS. M. OHADWIOK,

L. A. 'CONNER, Jr.

50 to my invention sounds were transmitted by 

